C-kit Receptor Research Articles

Evaluation Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic patients

Background: Mast cells play an essential role in pathology of bronchial asthma. Stem cell factor (SCF) is a major mast cell growth factor, which could be involved in the local increase of mast cell number in the asthmatic airways when bind to its receptor (C-kit). Existing study aimed to evaluate role of gene expression of SCF and their receptor C-kit in development of bronchial asthma in Iraqi population. Methods: present study included 100 patients diagnostic with bronchial asthma (59 females and 41 males) their ages range from 2 to 61 years and 30 healthy individuals (14 females and 16 males) with the same age range as control group DNA extracted from whole blood samples and then subjected to real time PCR for detection of gene expression. Results: current data showed a significant correlation (p0.05) . The optimum cut-off values for gene expression of SCF and C-kit are ≥ 0.55, ≥2.328 respectively since there are associated with a perfect test for predicting asthma. In conclusion: high gene expression of SCF and C-kit associated with increase severity stage of bronchial asthma without treatment and can be reduced by treatment. How to Cite this Article Pubmed Style MUBARK NN, AL-MAAMORI JA, GHALI KH. Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic SRP. 2020; 11(1): 51-57. doi:10.5530/srp.2020.1.08 Web Style MUBARK NN, AL-MAAMORI JA, GHALI KH. Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic http://www.sysrevpharm.org/?mno=302645230 [Access: March 29, 2021]. doi:10.5530/srp.2020.1.08 AMA (American Medical Association) Style MUBARK NN, AL-MAAMORI JA, GHALI KH. Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic SRP. 2020; 11(1): 51-57. doi:10.5530/srp.2020.1.08 Vancouver/ICMJE Style MUBARK NN, AL-MAAMORI JA, GHALI KH. Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic SRP. (2020), [cited March 29, 2021]; 11(1): 51-57. doi:10.5530/srp.2020.1.08 Harvard Style MUBARK, N. N., AL-MAAMORI, . J. A. & GHALI, . K. H. (2020) Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic SRP, 11 (1), 51-57. doi:10.5530/srp.2020.1.08 Turabian Style MUBARK, NAWRAS NAJAH, JAFAR A. AL-MAAMORI, and KAREEM HAMED GHALI. 2020. Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic Systematic Reviews in Pharmacy, 11 (1), 51-57. doi:10.5530/srp.2020.1.08 Chicago Style MUBARK, NAWRAS NAJAH, JAFAR A. AL-MAAMORI, and KAREEM HAMED GHALI. Evaluation Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic patients. Systematic Reviews in Pharmacy 11 (2020), 51-57. doi:10.5530/srp.2020.1.08 MLA (The Modern Language Association) Style MUBARK, NAWRAS NAJAH, JAFAR A. AL-MAAMORI, and KAREEM HAMED GHALI. Evaluation Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic patients. Systematic Reviews in Pharmacy 11.1 (2020), 51-57. Print. doi:10.5530/srp.2020.1.08 APA (American Psychological Association) Style MUBARK, N. N., AL-MAAMORI, . J. A. & GHALI, . K. H. (2020) Gene Expression of Stem Cell Factor and C-kit among Bronchial Asthmatic Systematic Reviews in Pharmacy, 11 (1), 51-57. doi:10.5530/srp.2020.1.08

Nevadensin relieves food allergic responses and passive cutaneous anaphylaxis in mice through inhibiting the expression of c-Kit receptors.

Nevadensin (NEV), a natural flavonoid compound derived from Lysionotus pauciflorus Maxim, has numerous biological activities. However, few researchers have examined its potential impact on alleviating allergies. In the present study, NEV was found to upregulate rectal temperature, suppress the development of diarrhea, and decrease the levels of serum specific immunoglobulin E, histamine and mouse MC protease-1 in ovalbumin-allergic mice. Moreover, NEV also alleviated passive cutaneous anaphylaxis reactions and inhibited the release of β-hexosaminidase and histamine in bone marrow-derived mast cells. Furthermore, we provide the first demonstration that NEV decreases the expression of c-Kit and suppresses the proliferation of bone marrow-derived mast cells and accelerates their apoptosis. These findings indicated that L. pauciflorus-derived NEV might have the potential to alleviate food hypersensitivity.

Imatinib attenuates neotissue formation during vascular remodeling in an arterial bioresorbable vascular graft

BackgroundBioresorbable vascular grafts (BVGs) can transform biologically into active blood vessels and represent an alternative to traditional synthetic conduits, which are prone to complications such as infection and thrombosis. Although platelet-derived growth factors and c-Kit positive cells play an important role in smooth muscle cell (SMC) migration and proliferation in vascular injury, atherosclerosis, or allograft, their roles in the vascular remodeling process of an arterial BVG remains unknown. Thus, we assessed the neottisue formation on arterial BVG remodeling by administrating imatinib, which is both a platelet-derived growth factor receptor kinase inhibitor and c-Kit receptor kinase inhibitor, in a murine model. MethodsBVGs were composed of an inner poly(L-lactic-co-ε-caprolactone) copolymer sponge layer and an outer electrospun poly(L-lactic acid) nanofiber layer, which were implanted into the infrarenal abdominal aortas of C57BL/6 mice. After graft implantation, saline or 100 mg/kg of imatinib was administrated intraperitoneally daily for 2 weeks (n = 20 per group). Five mice in each group were scheduled to be humanely killed at 3 weeks and 15 at 8 weeks, and BVGs were explanted for histologic assessments. ResultsGraft patency during the 8-week observational period was not significantly different between groups (control, 86.7% vs imatinib, 80.0%; P > .999). Neotissue formation consisting of endothelialization, smooth muscle proliferation, and deposition of collagen and elastin was not observed in either group at 3 weeks. Similar endothelialization was achieved in both groups at 8 weeks, but thickness and percent area of neotissue formation were significantly higher in the control group than in the imatinib group, (thickness, 30.1 ± 7.2 μm vs 19.6 ± 4.5 μm [P = .001]; percent area, 9.8 ± 2.7% vs 6.8 ± 1.8% [P = .005]). Furthermore, SMC layer and deposition of collagen and elastin were better organized at 8 weeks in the control group compared with the imatinib group. The thickness of SMC layer and collagen fiber area were significantly greater at 8 weeks in the control group than in the imatinib group (P < .001 and P = .026, respectively). Because there was no difference in the inner diameter of explanted BVGs (831.7 ± 63.4 μm vs 841.8 ± 41.9 μm; P = .689), neotissue formation was thought to advance toward the outer portion of the BVG with degradation of the polymer scaffold. ConclusionsImatinib attenuates neotissue formation during vascular remodeling in arterial bioresorbable vascular grafts (BVGs) by inhibiting SMC layer formation and extracellular matrix deposition.

Co-Occurrence of neurofibromatosis-1 with urticaria pigmentosa: A Coincidental association?

Neurofibromatosis-1 (NF-1) is a neuroectodermal abnormality characterized by multiple neurofibromas, café-au-lait macules, axillary freckling, and Lisch nodules. Urticaria pigmentosa (UP) is a maculopapular cutaneous mastocytosis due to mast cell hyperplasia. We report a case of NF-1 associated with UP. A 19-year-old male presented with multiple neurofibromas, café-au-lait macules, axillary freckling, and Lisch nodules. He also had UP lesions with positive Darier's sign. A clinical diagnosis of NF-1 with UP was made and confirmed histopathologically. Mastocytosis exhibits mast cell hyperplasia due to C-kit gene mutation. Mast cell mediatiors directly contribute to neurofibroma growth. C-kit receptor abnormality is implicated in the formation of neurofibromas as well as in UP. With possible interconnected underlying pathology of mast cell hyperplasia and increased mast cell mediators in both UP and NF-1, a possible association of NF and UP beyond simple coincidence should be considered.

Interstitial cells of Cajal in Wsh/Wsh c-kit mutant mice.

The c-Kit receptor tyrosine kinase regulates the development and differentiation of several progenitor cells. In the gastrointestinal (GI) tract, the c-Kit regulates the development of the interstitial cells of Cajal (ICC) that are responsible for motility regulation of the GI musculature. W-sash (Wsh) is an inversion mutation upstream of the c-kit promoter region that affects a key regulatory element, resulting in cell-type-specific altered gene expression, leading to a decrease in the number of mast cells, melanocytes, and ICC. We extensively examined the GI tract of Wsh/Wsh mice using immunohistochemistry and electron microscopy. Although the musculature of the Wsh/Wsh mice did not show any c-Kit immunoreactivity, we detected intensive immunoreactivity for transmembrane member 16A (TMEM16A, anoctamin-1), another ICC marker. TMEM16A immunopositive cells were observed as ICC-MY in the gastric corpus-antrum and the large intestine, ICC-DMP in the small intestine, and ICC-SM in the colon. Electron microscopic analysis revealed these cells as ICC from their ultrastructural features, such as numerous mitochondria and caveolae, and their close contact with nerve terminals. In the developmental period, we examined 14.5 and 18.5 day embryos but did not observe c-Kit immunoreactivity in the Wsh/Wsh small intestine. From this study, ICC subtypes developed and maturated structurally without c-Kit expression. Wsh/Wsh mice are a new model to investigate the effects of c-Kit and unknown signaling on ICC development and function.

Immunohistochemical study assessing stem cell factor receptor C-kit in patients with alopecia

Background Stem cell factor receptor c-kit is a transmembrane protein with tyrosine kinase activity encoded by the oncogene c-kit. The stem cell factor/c-kit signaling may be involved in the pathological processes of alopecia. Objective The aim was to elucidate the role of the stem cell factor receptor c-kit in the pathogenesis of some types of alopecia. Patients and methods The study included 80 patients (52 had alopecia areata and 28 had androgenetic alopecia), in addition to 40 normal healthy persons who served as a control group. Skin biopsies were obtained from each participant and stained with hematoxylin and eosin and stem cell factor receptor c-kit. Results There was a statistically significant increase in intensity and count of stem cell factor receptor c-kit-positive cell expression in alopecia areata and androgenetic alopecia than in normal control specimens. There was a positive correlation between the intensity and count of stem cell factor receptor c-kit-positive cells in relation to the severity of alopecia. Conclusions Stem cell factor receptor c-kit was implicated in the pathogenesis of alopecia areata and androgenic alopecia, and it could have a predictive role in the progression of alopecia in high-risk patients.

Schwann cells orchestrate peripheral nerve inflammation through the expression of CSF1, IL-34, and SCF in amyotrophic lateral sclerosis.

Distal axonopathy is a recognized pathological feature of amyotrophic lateral sclerosis (ALS). In the peripheral nerves of ALS patients, motor axon loss elicits a Wallerian-like degeneration characterized by denervated Schwann cells (SCs) together with immune cell infiltration. However, the pathogenic significance of denervated SCs accumulating following impaired axonal growth in ALS remains unclear. Here, we analyze SC phenotypes in sciatic nerves of ALS patients and paralytic SOD1G93A rats, and identify remarkably similar and specific reactive SC phenotypes based on the pattern of S100β, GFAP, isolectin and/or p75NTR immunoreactivity. Different subsets of reactive SCs expressed colony-stimulating factor-1 (CSF1) and Interleukin-34 (IL-34) and closely interacted with numerous endoneurial CSF-1R-expressing monocyte/macrophages, suggesting a paracrine mechanism of myeloid cell expansion and activation. SCs bearing phagocytic phenotypes as well as endoneurial macrophages expressed stem cell factor (SCF), a trophic factor that attracts and activates mast cells through the c-Kit receptor. Notably, a subpopulation of Ki67+ SCs expressed c-Kit in the sciatic nerves of SOD1G93A rats, suggesting a signaling pathway that fuels SC proliferation in ALS. c-Kit+ mast cells were also abundant in the sciatic nerve from ALS donors but not in controls. Pharmacological inhibition of CSF-1R and c-Kit with masitinib in SOD1G93A rats potently reduced SC reactivity and immune cell infiltration in the sciatic nerve and ventral roots, suggesting a mechanism by which the drug ameliorates peripheral nerve pathology. These findings provide strong evidence for a previously unknown inflammatory mechanism triggered by SCs in ALS peripheral nerves that has broad application in developing novel therapies.

Inhibition of the stem cell factor 248 isoform attenuates the development of pulmonary remodeling disease.

Stem cell factor (SCF) and its receptor c-kit have been implicated in inflammation, tissue remodeling, and fibrosis. Ingenuity Integrated Pathway Analysis of gene expression array data sets showed an upregulation of SCF transcripts in idiopathic pulmonary fibrosis (IPF) lung biopsies compared with tissue from nonfibrotic lungs that are further increased in rapid progressive disease. SCF248, a cleavable isoform of SCF, was abundantly and preferentially expressed in human lung fibroblasts and fibrotic mouse lungs relative to the SCF220 isoform. In fibroblast-mast cell coculture studies, blockade of SCF248 using a novel isoform-specific anti-SCF248 monoclonal antibody (anti-SCF248), attenuated the expression of COL1A1, COL3A1, and FN1 transcripts in cocultured IPF but not normal lung fibroblasts. Administration of anti-SCF248 on days 8 and 12 after bleomycin instillation in mice significantly reduced fibrotic lung remodeling and col1al, fn1, acta2, tgfb, and ccl2 transcript expression. In addition, bleomycin increased numbers of c-kit+ mast cells, eosinophils, and ILC2 in lungs of mice, whereas they were not significantly increased in anti-SCF248-treated animals. Finally, mesenchymal cell-specific deletion of SCF significantly attenuated bleomycin-mediated lung fibrosis and associated fibrotic gene expression. Collectively, these data demonstrate that SCF is upregulated in diseased IPF lungs and blocking SCF248 isoform significantly ameliorates fibrotic lung remodeling in vivo suggesting that it may be a therapeutic target for fibrotic lung diseases.

C-Kit-stem cell factor signal-independent development of interstitial cells of Cajal in murine small intestine.

c-Kit receptor tyrosine kinase and its ligand stem cell factor (SCF) play critical roles in regulating the development and proliferation of various cells, including the interstitial cells of Cajal (ICC) in the gastrointestinal tract. Many subtypes of ICC are known to be lacking in c-Kit-SCF-insufficient mice, such as W/Wv and Sl/Sld, whereas ICC-deep muscular plexus (DMP) in small intestine are not lacking. In this study, we examine ICC-DMP development in normal and c-Kit-SCF signal-insufficient mice. In normal mice, numerous ICC-DMP labeled with c-Kit and neurokinin 1 receptor (NK1R) antibodies were observed only in the duodenum on the day of birth, in the duodenum and the jejunum on postnatal day 4 and throughout the small intestine after postnatal day 6. In W mutant mice (W/Wv, Wv/Wv, W/W), ICC-DMP investigated using c-Kit and NK1R immunoreactivities were similar to that in normal mice. c-Kit ligand SCF-deficient mice (Sl/Sl) also showed almost identical ICC-DMP development and proliferation as normal mice. These results show that the development and proliferation of ICC-DMP occur in the postnatal period independent of c-Kit-SCF signaling.

Cancer Stem Cells and Neuroblastoma: Characteristics and Therapeutic Targeting Options.

The majority of embryonal tumors or childhood blastomas derive from pluripotent progenitors or fetal stem cells that acquire cancer stem cell (CSC) properties: multipotency, self-renewal ability, metastatic potential, chemoresistance, more pronounced levels of drug transporters, enhanced DNA-damage repair mechanisms, and a quiescent state. Neuroblastoma (NB) is considered a neuroendocrine tumor and is the most common extracranial neoplasm in children. NB pathogenesis has frequently been associated with epigenetic dysregulation and a failure to implement a differentiation program. The origin, characteristics, and isolation of the CSC subpopulation in NB are still incompletely understood, despite the evidence that this cell subset contributes to disease recurrence and acquired resistance to standard therapies. Here, we summarize the literature regarding the isolation and characterization of CSCs in NB over the past decades, from the early recognition of the expression of stem cell factor (SCF) or its receptor c-KIT to more recent studies identifying the ability of G-CSF and STAT3 to support stem cell-like properties in NB cells. Additionally, we review the morphological variants of NB tumors whose recent epigenetic analyses have shed light on the tumor heterogeneity so common in NB. NB-derived mesenchymal stem cells have recently been isolated from primary tumors of NB patients and associated with a pro-tumorigenic role in the tumor microenvironment, enabling immune escape by tumors, and contributing to their invasive and metastatic capabilities. In particular, we will focus on epigenetic reprogramming in the CSC subpopulation in NB and strategies to target CSCs in NB.

Identification of a Multitargeted Tyrosine Kinase Inhibitor for the Treatment of Gastrointestinal Stromal Tumors and Acute Myeloid Leukemia.

Gastrointestinal stromal tumors (GISTs) are prototypes of stem cell factor receptor (c-KIT)-driven cancer. Two receptor tyrosine kinases, c-KIT and fms-tyrosine kinase (FLT3), are frequently mutated in acute myeloid leukemia (AML) patients, and these mutations are associated with poor prognosis. In this study, we discovered a multitargeted tyrosine kinase inhibitor, compound 15a, with potent inhibition against single or double mutations of c-KIT developed in GISTs. Moreover, crystal structure analysis revealed the unique binding mode of 15a with c-KIT and may elucidate its high potency in inhibiting c-KIT kinase activity. Compound 15a inhibited cell proliferation and induced apoptosis by targeting c-KIT in c-KIT-mutant GIST cell lines. The antitumor effects of 15a were also demonstrated in GIST430 and GIST patient-derived xenograft models. Further studies demonstrated that 15a inhibited the proliferation of c-KIT- and FLT3-driven AML cells in vitro and in vivo. The results of this study suggest that 15a may be a potential anticancer drug for the treatment of GISTs and AML.

CD117 Expression Is Associated with Cytogenetic and Molecular Profiles and Outcome in Pediatric Acute Myeloid Leukemia

Cell surface antigen expression in AML is becoming focus of investigation as it relates to prognostic impact as well as potential therapeutic implications. The CD117 (c-KIT) receptor tyrosine kinase is expressed on the cell surface of hematopoietic stem cells and its signaling is important in cell survival, proliferation and differentiation. CD117 is expressed in a majority of AML cases. In addition, mutations in c-KIT have been identified in a subset of patients, specifically those with CBF AML (inv(16)/t(16;16) and t(8;21)). As there is increasing interest in using tyrosine kinase inhibitors with anti-KIT activity based on surface CD117 expression as treatment in AML, we sought to evaluate the association of CD117 expression with biologic and clinical features in pediatric and young adult (YA) AML. A total of 1803 pediatric and YA patients (ages 0.01-29.2 years) treated on the Children's Oncology Group (COG) phase III trials AAML0531 (n=762) and AAML1031 (n=1041) with complete cyto/molecular and outcome data available were included in the analysis. The primary aim of AAML0531 evaluated the addition of gemtuzumab ozogamicin to a 5-course MRC-based backbone, while AAML1031 evaluated the addition of bortezomib to a similar 4-course backbone. Outcomes between the 2 primary randomized arms on each trial were similar and thus were included together for each trial. Multidimensional flow cytometry was used to determine the CD117 mean fluorescence intensity (MFI) of myeloid progenitor cells as defined by CD45 low and side scatter using a CD117-PE antibody with stable intensity detection since 2002. Patients were divided into quartiles based on CD117 expression and clinical characteristics and outcome were evaluated across the quartiles. CD117 MFI distribution was similar across both trials (Fig 1A). Analysis of CD117 expression with cytogenetics demonstrated that t(8;21) was significantly associated with higher CD117 (p&lt;0.001), with 72% of patients demonstrating expression above the median (Fig 1B). Similarly, inv(16) was associated with higher CD117 (p&lt;0.001), with 76% of patients with CD117 MFI above the median (Fig 1B). In contrast, CD117 expression was inversely associated with KMT2A rearrangements (p&lt;0.001), with 82% of patients with CD117 MFI below the median (Fig 1B). Evaluation of CD117 expression according to risk stratifying mutations demonstrated higher expression among patients with CEBPA mutations, with 76% of CEBPA-mutant patients with CD118 MFI above the median (Fig 1C). In contrast, CD117 expression was inversely associated with NPM1 mutations (p&lt;0.001) as 63% of patients had expression below the median (Fig 1B). Significant differences in CD117 expression across all the quartiles was seen among FLT3/ITD patients, with the majority of patients (63%) in Q2-Q3, with 18% and 19% in Q1 and Q4 respectively (0&lt;0.001; Fig 1C), and a similar pattern was seen among the HAR subset. Outcome analysis demonstrated that CD117 surface expression was not associated with CR, with similar CR rates across the quartiles (p=0.726). In a univariate analysis, overall survival (OS) was associated with higher CD117 expression (p&lt;0.001), with higher OS in Q3-Q4 (65% and 70% respectively) compared to Q1 and Q2 (61% and 58% respectively; Fig 1D). Similarly, improved disease free survival (DFS) was associated with higher CD117 expression, with higher DFS in Q3/Q4 (58% and 60% respectively) compared to 48% each in Q1 and Q2 (p&lt;0.001). This was driven by a higher relapse risk in Q1/2 (45% each) compared to Q3/4 (39% and 36% respectively; p=0.001). Analysis in the CBF cohort demonstrated no significant differences in outcome (p=NS in OS, DFS, and relapse risk) across the quartiles (Fig 1E). We show here that CD117 expression was higher in patients with favorable risk CBF AML and inversely associated with KMT2A rearrangements, which are generally considered to be neutral or unfavorable depending on the specific translocation partner. Higher CD117 expression was associated with improved outcomes, which may in part be explained by the association with CBF and inverse association with KMT2A. Although patients with higher CD117 MFI generally have favorable risk genomic alterations, the strategy of c-KIT inhibition warrants further investigation in AML given the potential for facilitating de-escalation of conventional therapeutics with significant toxicity in future clinical trials if found to be safe and effective. Disclosures Eidenschink Brodersen: Hematologics, Inc: Employment. Pardo:Hematologics, Inc: Employment. Dai:Hematologics, Inc: Employment. Loken:Hematologics, Inc: Employment, Equity Ownership.

Novel Lymphoid Pathway of Human Plasmacytoid and Conventional Dendritic Cells

[Introduction] Dendritic cells (DCs) play a central role in initiation and regulation of immune response. Human plasmacytoid DCs (pDCs) as well as conventional DCs (cDCs) were shown to differentiate from multi-lymphoid progenitors (MLPs) as well as myeloid progenitors via common DC progenitors. However, lymphoid pathway of DCs remained clarified. Here we investigated lymphoid origin of DCs, using a novel co-culture system which supports differentiation of various lineages of lymphoid and DCs (Br J Haematol. 157:674, 2012; J Immunol. 199:2343, 2017). [Methods and Results] CD34+CD38-CD45RA-CD10-CD7- human hematopoietic stem/progenitor cells (HSPCs) and various lymphoid progenitors including CD34+CD38-CD45RA+CD10-CD7-lymphoid-primed multipotent progenitors (LMPPs), CD34+CD38-CD45RA+CD10+ MLPs,and CD34+CD38+CD45RA+CD10+CD7-CD19- (10SPs), generally though as B/NK progenitors, were isolated from cord blood and cocultured with telomerized human stromal cells with SCF, flt3L, TPO, and GM-CSF. After 17 to 21 days, generation of CD45RA+CD19+ proB, CD56+CD3- NK cells, HLA-DR+IL-3RhighCD303+CD304+pDCs, and CD1c+cDCs was assessed. We observed that not only immature HSPCs, LMPPs and MLPs but also 10SPs gave rise to pDC and cDCs in addition to proB, NK cells. 10SPs were found to be subdivided by expression pattern of c-kit and IL-7 receptor (R), and similarly cocultured with stromal cells. pDCs, cDCs, proB, and NK cells were generated from c-kit+IL-7R- fraction, while pDC, cDCs, and proB, but few or no NK cells were generated from c-kit+IL-7R+ fractions. c-kit-IL-7R+ fraction produced a significantly lower number of cells than c-kit+IL-7R+or- fractions and mainly differentiated into proB cells. By single cell assay of 10SPs, progenitors with differentiation potential for pDC, cDC, and/or proB were detected. These data revealed a differentiation pathway of pDCs and cDCs from relatively mature lymphoid progenitors and suggested the presence of DC and B common progenitors. [Summary] The present study uncovered a closed relationship between B-lymphoid and DC differentiation pathway. We are further attempting to delineate their relationship and differentiation process toward pDCs, cDCs, and proB. Disclosures Nagaharu: kyowa hakko kirin: Research Funding; Astellas Pharma: Research Funding; Nippon Shinyaku: Research Funding; Ono Pharmaceutical: Research Funding. Ohishi:kyowa hakko kirin: Research Funding; Nippon Shinyaku: Research Funding; Astellas Pharma: Research Funding; Ono Pharmaceutical: Research Funding. Katayama:Sysmex: Honoraria; Taisho Toyama Pharma: Honoraria; Celgene: Honoraria; Pfizer: Honoraria; Alexion Pharmaceuticals: Honoraria; Chugai: Honoraria; Nippon Shinyaku: Honoraria, Research Funding; Sumitomo Dainippon Pharma: Honoraria; Ono Pharmaceutical: Research Funding; Novo Nordisk: Honoraria; Shionogi Pharmaceutical: Honoraria; Shire: Honoraria; Novartis: Honoraria; Astellas Pharma: Honoraria, Research Funding; Takeda: Honoraria; Bristol-Myers Squibb: Honoraria; kyowa hakko kirin: Honoraria, Research Funding.

An All Antibody Approach for Conditioning Bone Marrow for Hematopoietic Stem Cell Transplantation with Anti-cKIT and Anti-CD47 in Non-Human Primates

An All Antibody Approach for Conditioning Bone Marrow for Hematopoietic Stem Cell Transplantation with Anti-cKIT and Anti-CD47 in Non-Human Primates

Discovery of a ‘Grail-Shaped’ Drug: Ne-ratinib and the Downregulation of Mutant RAS

It has been stated that developing a drug that can attack mutated RAS proteins is ‘the Holy Grail’ of cancer therapeutics. Through a series of unexpected findings, the authors discovered that the irreversible epidermal growth factor receptor 1/2/4 inhibitor neratinib (HKI-272, Nerlynx®) was not only an inhibitor of those receptor tyrosine kinases, but could additionally cause receptor internalisation and degradation. To the author’s surprise, the negative control receptors c-MET and c-KIT were also degraded after neratinib exposure, albeit with a slower time-course. This appeared to be attributable to neratinib attacking receptor tyrosine kinases localised in quaternary structures. It was reasoned that neratinib had the potential to downregulate the expression of other plasma membrane localised signalling proteins, particularly RAS. In a variety of tumour types, neratinib could reduce the expression of wild type (Kirsten) and mutant (Neuroblastoma) RAS (K-RAS/N-RAS, respectively). It was subsequently demonstrated that mutant Gα proteins in uveal melanoma could also have their expression reduced by neratinib. Neratinib was shown to be an inhibitor of sterile 20 serine/threonine kinases. Acting as an inhibitor of sterile 20 serine/threonine kinases, combined with RAS inhibition, neratinib enhanced the phosphorylation and degradation of the Hippo pathway effectors yes-associated protein and transcriptional coactivator with PDZ-binding motif. In malignancies expressing a mutant K-RAS, yes-associated protein and transcriptional coactivator with PDZ-binding motif are localised in the nucleus where they cooperate with mutant K-RAS signalling to promote growth, invasion, and chemotherapy resistance. Thus, whilst neratinib is not a direct inhibitor of mutant RAS signalling, the Holy Grail, it nonetheless represents, as did the beacon atop Castle Anthrax, at least something ‘Grail-shaped’.

Screening Yeast Display Libraries against Magnetized Yeast Cell Targets Enables Efficient Isolation of Membrane Protein Binders.

When isolating binders from yeast displayed combinatorial libraries, a soluble, recombinantly expressed form of the target protein is typically utilized. As an alternative, we describe the use of target proteins displayed as surface fusions on magnetized yeast cells. In our strategy, the target protein is coexpressed on the yeast surface with an iron oxide binding protein; incubation of these yeast cells with iron oxide nanoparticles results in their magnetization. Subsequently, binder cells that interact with the magnetized target cells can be isolated using a magnet. Using a known binder-target pair with modest binding affinity (KD ≈ 400 nM), we showed that a binder present at low frequency (1 in 105) could be enriched more than 100-fold, in a single round of screening, suggesting feasibility of screening combinatorial libraries. Subsequently, we screened yeast display libraries of Sso7d and nanobody variants against yeast displayed targets to isolate binders specific to the cytosolic domain of the mitochondrial membrane protein TOM22 (KD ≈ 272-1934 nM) and the extracellular domain of the c-Kit receptor (KD ≈ 93 to KD > 2000 nM). Additional studies showed that the TOM22 binders identified using this approach could be used for the enrichment of mitochondria from cell lysates, thereby confirming binding to the native mitochondrial protein. The ease of expressing a membrane protein or a domain thereof as a yeast cell surface fusion-in contrast to recombinant soluble expression-makes the use of yeast-displayed targets particularly attractive. Therefore, we expect the use of magnetized yeast cell targets will enable efficient isolation of binders to membrane proteins.

Serum Stem Cell Factor Level Predicts Decline in Kidney Function in Healthy Aging Adults.

Stem cell factor (SCF), the ligand of the c-kit receptor, actively participates in the organ reconstruction and fibrosis associated with various diseases, including kidney disease. However, it remains unclear whether SCF plays a role in kidney aging. In the present study, we measured the serum SCF level, estimated glomerular filtration rate (eGFR), and other biological parameters in a Chinese Han group of 892 subjects, and explored the relationship between SCF level and renal function during aging; we sought to define novel biomarkers of kidney aging. Multiple linear regression was used to select potential indicators of decline in renal function. Only age, SCF level, and 25% maximum expiratory flow (25% MEF) were significant predictors after redundancy analysis (|r| > 0.70 and P < 0.05). Multiple linear regression showed that the relationship among eGFR, SCF level, and age could be described as follows: eGFR = 154.486 - (0.846 × age) - (0.011 × SCF level). We found no between-gender difference in the effect of SCF on kidney aging. In conclusion, the SCF level is an ideal biomarker of renal aging and may help to predict changes in eGFR during aging.

Serum level of stem cell factor and its soluble receptor in aspirin-exacerbated respiratory disease

Aim: Stem cell factor (SCF) may be associated with inflammatory processes leading to aspirin-induced asthma. This study evaluated the relationship between serum level of SCF and its soluble receptor with aspirin-induced asthma. Methods & materials: Twenty-five patients and 25 healthy controls were enrolled in this study. The concentration of SCF and mast/stem cell growth factor receptor (C-kit) was determined in serum samples. Spirometry and rhinometry were performed to determine the severity of the disease. p < 0.05 were considered significant. Results: The serum levels of SCF and C-kit receptor were significantly higher in the case group. The serum SCF and C-kit level had a significant positive correlation with the severity of asthma, disease duration and nasal obstruction. Conclusion: Our findings suggest that SCF and C-kit receptors have a direct effect on the severity of aspirin-induced asthma.

Role of CD135/CD117 on Prognosis and Overall Survival of Acute Myeloid Leukemia

Background:The key proliferative RTKs for AML include c-KIT receptor (CD117) and FLT-3 receptor (CD135). The aim of this study was to evaluate the CD135 and CD117 expression, co-expression of CD135 and CD117 (CD135+CD117), and the association of that co-expression with Event Free Survival (DFS) and Overall Survival (OS) rates. Material and Methods:We analyzed CD117 and CD135 expression on AML blasts by flow cytometry and its association with Event Free Survival (DFS) and Overall Survival (OS) in 66 AML treated on Hematology-Oncology Research Center, Iran, Tabriz. Results:The overall OS and EFS were 50% and 80.3% respectively during our study. Cox-regression analysis revealed that a poor EFS was significantly associated a low CD135 (HR 0.34, 95% CI 0.13–0.88, P = 0.02). Conclusion:This is the first study from Iran to show that the expressions of CD135, CD117 is easily measurable by routine diagnostic flow-cytometry, and CD135+117 were not significantly associated with CR, EFS, or OS .

An evaluation of masitinib for treating systemic mastocytosis

ABSTRACTIntroduction: Systemic Mastocytosis (SM) is a complex family of rare diseases, against which pharmacological therapies are still very few. It is a c-kit driven disease, whose disregulation leads to uncontrolled activation and proliferation of mast cells (MCs) with consequent release of effector molecules which are responsible for its clinical manifestations.Areas covered: Masitinib is a relatively new potential drug against SM and its chemical structure strictly derives from imatinib, the first tyrosine kinase inhibitor which entered the pharmaceutical market about 15 years ago. In this review, the authors present masitinib in all its properties, from chemistry to pharmacology and toxicity to its potential clinical application in SM, focusing the discussion on the few clinical trials in which it has been involved, with a particular attention on the still open challenge to determine how to measure the response to therapy.Expert opinion: In spite of their similarity in chemistry and biological activity against submolecular targets, masitinib is much more selective towards c-kit receptors than other tyrosine kinases, such as Bcl-Abl. Furthermore, its ability to inhibit degranulation, cytokine production and MCs migration from bone marrow gives it a great chance to become an important therapeutic option for selected SM patients.